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Investing & Retirement

Free investing & retirement calculators: compound interest, 401(k), Roth IRA, investment return, savings goal, net worth, RMD and Coast FIRE — with formulas.

9 calculators Free and online

📌 About Investing & Retirement

Time and compounding do the heavy lifting in building wealth, but the numbers are hard to picture in your head. These calculators turn contributions, rates and years into a real future balance — so you can see why starting early beats saving more later, how an employer 401(k) match stacks up against a Roth IRA, and what it takes to reach a savings goal or a Coast FIRE number.

Each tool shows the formula and a worked example in US dollars. Use them to project compound growth, compare account types, track your net worth, or figure your required minimum distribution (RMD) in retirement — and remember these are educational estimates, not personalized financial advice.

  • Project compound interest and investment growth with regular contributions
  • Compare a 401(k) employer match against a Roth IRA
  • Work backward from a savings goal or target retirement date
  • Find your Coast FIRE number — the point you can stop contributing
  • Track your net worth (assets minus liabilities) over time
  • Estimate your required minimum distribution (RMD) after age 73

🧮 Calculators in this category

Planning

Inflation Calculator — Future Cost & Buying Power Over Time
See what today's dollars will cost down the road, and how much purchasing power they lose, at any average inflation rate.
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Net Worth Calculator — Assets Minus Liabilities, the Real Number
Add up everything you own, subtract everything you owe, and see your true net worth — assets minus liabilities — with a clear breakdown.
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Retirement & Accounts

401(k) Calculator — Project Your Retirement Balance with Employer Match
See how your employer match, pre-tax salary deferrals, the 2025 $23,500 cap and annual raises stack up into a retirement balance — and how much of it is free match money you'd lose by under-contributing.
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Roth IRA Calculator — Tax-Free Retirement Balance & Growth
Project the tax-free balance your Roth IRA could reach by retirement — from your current age, balance, yearly contributions and expected return — and see how much is growth versus what you put in.
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Coast FIRE Calculator — When You Can Stop Saving for Retirement
Find the amount you'd need invested today so it grows to your full FIRE number by retirement — with no further contributions. See if you've already hit Coast FIRE and by how much.
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RMD Calculator — Required Minimum Distribution for IRAs & 401(k)s
Estimate your required minimum distribution (RMD) from a traditional IRA or 401(k) using the IRS Uniform Lifetime Table.
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Saving & Growth

Compound Interest Calculator — Future Value with Monthly Contributions
See how a starting balance plus monthly deposits grows over time — future value, total contributions, and interest earned, with the formula and year-by-year breakdown.
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Investment Return Calculator — ROI, Total Gain & Annualized Return (CAGR)
Measure how a past investment actually performed: total dollar gain, total return %, and the annualized return (CAGR) you really earned per year.
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Savings Goal Calculator — Monthly Contribution & Time to Reach Your Target
Find the monthly amount you need to hit a savings goal by a target date — or how long it takes at a set monthly deposit, with interest factored in.
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📝 Related articles

Read more about this topic on our blog.

401(k) vs Roth IRA: Which Should You Fund First?
The smart funding order is match, then Roth IRA, then max your 401(k). Here's how pre-tax and after-tax accounts compare, with 2025 limits and a worked example.
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How Much Should You Have Saved by Each Age?
Wondering how much you should have saved by 30, 40, or 50? Here are the popular salary-multiple benchmarks, why they're guidelines not rules, and how to catch up.
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The Power of Compound Interest (Why Starting Early Wins)
Compound interest is interest earning interest. Here's how it works, the Rule of 72, and why starting at 25 beats a 35-year-old saving twice as much.
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Roth IRA Rules and Income Limits for 2025
Everything you need for 2025: the $7,000 Roth IRA limit, MAGI phase-out ranges for single and married filers, the 5-year rule, tax-free withdrawals, and no RMDs.
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❓ Frequently asked questions

What is compound interest?

Compound interest is interest earned on both your original principal and the interest already added. Over years it grows your balance far faster than simple interest, which is why time in the market matters so much.

Should I use a 401(k) or a Roth IRA?

Contribute to a 401(k) up to the full employer match first — that match is an instant, guaranteed return. After the match, many people max a Roth IRA (tax-free growth) before going back to the 401(k).

How much should I save each month?

It depends on your goal, timeline and expected return. Use the savings goal or compound interest calculator to work backward from the amount and date you're targeting, then adjust your monthly contribution.

What is an RMD and when does it start?

A required minimum distribution is the amount you must withdraw each year from most tax-deferred retirement accounts. Under the SECURE 2.0 Act, RMDs generally begin at age 73.